compiler_rt: Update Windows ABI for float<->int conversion routines

Starting with LLVM 14, the Libcalls to these functions are now lowered
using a Vec(2, u64) instead of the standard ABI for i128 integers, so
our compiler-rt implementation needs to be updated to expose the same
ABI on Windows.

lib/compiler_rt/fixdfti.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixdfti, .{ .name = "__fixdfti", .linkage = common.linkage });
+    const fixdfti_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __fixdfti_windows_x86_64;
+    } else __fixdfti;
+
+    @export(fixdfti_fn, .{ .name = "__fixdfti", .linkage = common.linkage });
 }
 
 pub fn __fixdfti(a: f64) callconv(.C) i128 {
     return floatToInt(i128, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __fixdfti_windows_x86_64(a: f64) callconv(.C) v128 {
+    return @bitCast(v128, floatToInt(i128, a));
+}

lib/compiler_rt/fixhfti.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixhfti, .{ .name = "__fixhfti", .linkage = common.linkage });
+    const fixhfti_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __fixhfti_windows_x86_64;
+    } else __fixhfti;
+
+    @export(fixhfti_fn, .{ .name = "__fixhfti", .linkage = common.linkage });
 }
 
-fn __fixhfti(a: f16) callconv(.C) i128 {
+pub fn __fixhfti(a: f16) callconv(.C) i128 {
     return floatToInt(i128, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __fixhfti_windows_x86_64(a: f16) callconv(.C) v128 {
+    return @bitCast(v128, floatToInt(i128, a));
+}

lib/compiler_rt/fixsfti.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixsfti, .{ .name = "__fixsfti", .linkage = common.linkage });
+    const fixsfti_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __fixsfti_windows_x86_64;
+    } else __fixsfti;
+
+    @export(fixsfti_fn, .{ .name = "__fixsfti", .linkage = common.linkage });
 }
 
 pub fn __fixsfti(a: f32) callconv(.C) i128 {
     return floatToInt(i128, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __fixsfti_windows_x86_64(a: f32) callconv(.C) v128 {
+    return @bitCast(v128, floatToInt(i128, a));
+}

lib/compiler_rt/fixtfti.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixtfti, .{ .name = "__fixtfti", .linkage = common.linkage });
+    const fixtfti_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __fixtfti_windows_x86_64;
+    } else __fixtfti;
+
+    @export(fixtfti_fn, .{ .name = "__fixtfti", .linkage = common.linkage });
 }
 
 pub fn __fixtfti(a: f128) callconv(.C) i128 {
     return floatToInt(i128, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __fixtfti_windows_x86_64(a: f128) callconv(.C) v128 {
+    return @bitCast(v128, floatToInt(i128, a));
+}

lib/compiler_rt/fixunsdfti.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixunsdfti, .{ .name = "__fixunsdfti", .linkage = common.linkage });
+    const fixunsdfti_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __fixunsdfti_windows_x86_64;
+    } else __fixunsdfti;
+
+    @export(fixunsdfti_fn, .{ .name = "__fixunsdfti", .linkage = common.linkage });
 }
 
 pub fn __fixunsdfti(a: f64) callconv(.C) u128 {
     return floatToInt(u128, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __fixunsdfti_windows_x86_64(a: f64) callconv(.C) v128 {
+    return @bitCast(v128, floatToInt(u128, a));
+}

lib/compiler_rt/fixunshfti.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixunshfti, .{ .name = "__fixunshfti", .linkage = common.linkage });
+    const fixunshfti_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __fixunshfti_windows_x86_64;
+    } else __fixunshfti;
+
+    @export(fixunshfti_fn, .{ .name = "__fixunshfti", .linkage = common.linkage });
 }
 
 pub fn __fixunshfti(a: f16) callconv(.C) u128 {
     return floatToInt(u128, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __fixunshfti_windows_x86_64(a: f16) callconv(.C) v128 {
+    return @bitCast(v128, floatToInt(u128, a));
+}

lib/compiler_rt/fixunssfti.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixunssfti, .{ .name = "__fixunssfti", .linkage = common.linkage });
+    const fixunssfti_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __fixunssfti_windows_x86_64;
+    } else __fixunssfti;
+
+    @export(fixunssfti_fn, .{ .name = "__fixunssfti", .linkage = common.linkage });
 }
 
 pub fn __fixunssfti(a: f32) callconv(.C) u128 {
     return floatToInt(u128, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __fixunssfti_windows_x86_64(a: f32) callconv(.C) v128 {
+    return @bitCast(v128, floatToInt(u128, a));
+}

lib/compiler_rt/fixunstfti.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixunstfti, .{ .name = "__fixunstfti", .linkage = common.linkage });
+    const fixunstfti_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __fixunstfti_windows_x86_64;
+    } else __fixunstfti;
+
+    @export(fixunstfti_fn, .{ .name = "__fixunstfti", .linkage = common.linkage });
 }
 
 pub fn __fixunstfti(a: f128) callconv(.C) u128 {
     return floatToInt(u128, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __fixunstfti_windows_x86_64(a: f128) callconv(.C) v128 {
+    return @bitCast(v128, floatToInt(u128, a));
+}

lib/compiler_rt/fixunsxfti.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixunsxfti, .{ .name = "__fixunsxfti", .linkage = common.linkage });
+    const fixunsxfti_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __fixunsxfti_windows_x86_64;
+    } else __fixunsxfti;
+
+    @export(fixunsxfti_fn, .{ .name = "__fixunsxfti", .linkage = common.linkage });
 }
 
 pub fn __fixunsxfti(a: f80) callconv(.C) u128 {
     return floatToInt(u128, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __fixunsxfti_windows_x86_64(a: f80) callconv(.C) v128 {
+    return @bitCast(v128, floatToInt(u128, a));
+}

lib/compiler_rt/fixxfti.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const floatToInt = @import("./float_to_int.zig").floatToInt;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__fixxfti, .{ .name = "__fixxfti", .linkage = common.linkage });
+    const fixxfti_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __fixxfti_windows_x86_64;
+    } else __fixxfti;
+
+    @export(fixxfti_fn, .{ .name = "__fixxfti", .linkage = common.linkage });
 }
 
-fn __fixxfti(a: f80) callconv(.C) i128 {
+pub fn __fixxfti(a: f80) callconv(.C) i128 {
     return floatToInt(i128, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __fixxfti_windows_x86_64(a: f80) callconv(.C) v128 {
+    return @bitCast(v128, floatToInt(i128, a));
+}

lib/compiler_rt/floattidf.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floattidf, .{ .name = "__floattidf", .linkage = common.linkage });
+    const floattidf_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __floattidf_windows_x86_64;
+    } else __floattidf;
+
+    @export(floattidf_fn, .{ .name = "__floattidf", .linkage = common.linkage });
 }
 
 pub fn __floattidf(a: i128) callconv(.C) f64 {
     return intToFloat(f64, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __floattidf_windows_x86_64(a: v128) callconv(.C) f64 {
+    return intToFloat(f64, @bitCast(i128, a));
+}

lib/compiler_rt/floattihf.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floattihf, .{ .name = "__floattihf", .linkage = common.linkage });
+    const floattihf_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __floattihf_windows_x86_64;
+    } else __floattihf;
+
+    @export(floattihf_fn, .{ .name = "__floattihf", .linkage = common.linkage });
 }
 
-fn __floattihf(a: i128) callconv(.C) f16 {
+pub fn __floattihf(a: i128) callconv(.C) f16 {
     return intToFloat(f16, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __floattihf_windows_x86_64(a: v128) callconv(.C) f16 {
+    return intToFloat(f16, @bitCast(i128, a));
+}

lib/compiler_rt/floattisf.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floattisf, .{ .name = "__floattisf", .linkage = common.linkage });
+    const floattisf_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __floattisf_windows_x86_64;
+    } else __floattisf;
+
+    @export(floattisf_fn, .{ .name = "__floattisf", .linkage = common.linkage });
 }
 
 pub fn __floattisf(a: i128) callconv(.C) f32 {
     return intToFloat(f32, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __floattisf_windows_x86_64(a: v128) callconv(.C) f32 {
+    return intToFloat(f32, @bitCast(i128, a));
+}

lib/compiler_rt/floattitf.zig

@@ -1,12 +1,26 @@
+const builtin = @import("builtin");
+const arch = builtin.cpu.arch;
 const common = @import("./common.zig");
 const intToFloat = @import("./int_to_float.zig").intToFloat;
 
 pub const panic = common.panic;
 
 comptime {
-    @export(__floattitf, .{ .name = "__floattitf", .linkage = common.linkage });
+    const floattitf_fn = if (builtin.os.tag == .windows and arch == .x86_64) b: {
+        // The "ti" functions must use Vector(2, u64) return types to adhere to the ABI
+        // that LLVM expects compiler-rt to have.
+        break :b __floattitf_windows_x86_64;
+    } else __floattitf;
+
+    @export(floattitf_fn, .{ .name = "__floattitf", .linkage = common.linkage });
 }
 
 pub fn __floattitf(a: i128) callconv(.C) f128 {
     return intToFloat(f128, a);
 }
+
+const v128 = @import("std").meta.Vector(2, u64);
+
+fn __floattitf_windows_x86_64(a: v128) callconv(.C) f128 {
+    return intToFloat(f128, @bitCast(i128, a));
+}